Early experimentation with vacuum insulated panels is evidenced in U.S. Pat. No. 948,541 (Coleman 1910). Later examples include U.S. Pat. No. 2,104,500 (Van Buren 1938) and U.S. Pat. No. 5,165,674 (Molthen 1992). Patent searches conducted by personnel at the Alberta Research Council and the University of Alberta, and another by a registered patent agent, yielded little that bore any similarity to the present panel. A vacuum is known to be the best nonconductor of heat, but it has not been successfully adapted to provide insulation in buildings.
Vacuum insulated building panels have generally consisted of an enclosed space in which a combination of insulating material and a partial vacuum impedes, heat transfer between the interior and exterior faces of such panels, the size of such panels being small, fitting between studs or covering, at most, an inside wall of a room. The faces and sides of these panels are rigidly constructed, either in one piece or the faces are secured by glue or other permanent means to a frame that forms the sides of the panel. Within the enclosed space, a separate structure supports the inside of the faces and sides of the panel to prevent inward collapse of the panel due to suction pressure of the vacuum.
The weather exposed face of a rigidly constructed panel expands and contracts due to wide temperature variations while the size of the other face changes little in comparison due to being maintained at close to building temperature. The panel warps, alternately in one direction then the other depending on the direction on temperature change, rendering it unusable.
A second previously unresolved problem caused by expansion and contraction of one face of a panel but not the other stresses the rigidly constructed support structures in other panels, said structures preventing the implosion of panel's due to vacuum pressure by maintaining the separation of their faces. Under vacuum, support structures are continuously forced to adjust position relative to the expanding or contracting face of the panel, an exercise for which they are not designed.
The above problems do not exist in the present panel.